The instant invention relates to apparatus for separating sheets of material, e.g. paper, and more particularly to a pneumatically actuated vacuum cup for opening the throat of an envelope.
Many paper handling devices have used vacuum force for a wide variety of applications. Vacuum force has been used in the mail handling industry to aid in the opening of envelopes in order for paper documents to be inserted into the envelopes. In a typical envelope inserting system using vacuum, an envelope is lying face down and a vacuum apparatus is located thereabove and includes a vacuum cup mounted on a lever arm which extends back to a type of mechanically pivoting device (the vacuum supply tube may or may not be incorporated into the lever arm). At the appropriate time, the pivoting device rotates in a first direction to drive the vacuum cup lever downward toward the envelope. When the vacuum cup contacts the envelope, the cup is evacuated so that the cup "acquires" the panel of the envelope. At this time the pivoting device reverses direction to drive the vacuum cup lever upward and thereby open the envelope.
Although the foregoing vacuum acquisition apparatus has traditionally been a successful method of opening envelopes, the mechanical complexity of the pivoting mechanism and associated components (vacuum lever arm, etc.) are very costly and serve to limit both speed and reliability.
Accordingly, the instant invention provides a pneumatically actuated vacuum cup for paper acquisition which eliminates the need for the mechanical elements associated with prior art vacuum cups.